Exhaust System Lessons

1

Lessons from dismantling the exhaust system:

I recently pulled an exhaust stud in #4 cylinder and had to remove most of the exhaust system to access it sufficiently to install a thread insert.

The reason for the pulled stud was that the flange on the #4 exhaust pipe was not parallel with the head; pulling the nut down resulted in stripping the thread in the head.  

Due to the usual rusted nuts and bolts, it took some time to get everything off, including the muffler and CAT.   On removing the muffler, I found a deep impression, caused by one of the muffler cradles, which had cracked through the outer skin and was happily rusting away.

On reassembly, I loosely assembled the whole system before progressively tightening everything.  This revealed two things: the flange on #4 exhaust pipe was now parallel and the RH muffler cradle was out of alignment.   There was nothing wrong with the #4 flange – it had just been carelessly assembled.

This indicates that the reassembly done the last time that the exhaust system was removed (not by me) did not involve any alignment, which resulted in the non-parallel flange and the deep cut in the muffler.

The installation of the thread insert was the quickest and easiest part of the job.   I had to buy a Recoil kit (from CBC $49) to get the insert tap.   It came with 10 inserts, so I now have 9 spares!

Les

2
Well done indeed.

Even looking at my exhaust system components, afraid I'll probably open up a pandoras box, except for a recently replaced tailpipe.

It's amazing though how the exhaust system keeps on keeping on.

Ken 

To: Syncro_T3_Australia@yahoogroups.com
From: leslieharris@optusnet.com.au
Date: Sun, 9 Oct 2011 02:41:09 +0000
Subject: [Syncro_T3_Australia] Exhaust System Lessons

 

Lessons from dismantling the exhaust system:

I recently pulled an exhaust stud in #4 cylinder and had to remove most of the exhaust system to access it sufficiently to install a thread insert.

The reason for the pulled stud was that the flange on the #4 exhaust pipe was not parallel with the head; pulling the nut down resulted in stripping the thread in the head.  

Due to the usual rusted nuts and bolts, it took some time to get everything off, including the muffler and CAT.   On removing the muffler, I found a deep impression, caused by one of the muffler cradles, which had cracked through the outer skin and was happily rusting away.

On reassembly, I loosely assembled the whole system before progressively tightening everything.  This revealed two things: the flange on #4 exhaust pipe was now parallel and the RH muffler cradle was out of alignment.   There was nothing wrong with the #4 flange – it had just been carelessly assembled.

This indicates that the reassembly done the last time that the exhaust system was removed (not by me) did not involve any alignment, which resulted in the non-parallel flange and the deep cut in the muffler.

The installation of the thread insert was the quickest and easiest part of the job.   I had to buy a Recoil kit (from CBC $49) to get the insert tap.   It came with 10 inserts, so I now have 9 spares!

Les